# Function not that directly used allowed? [duplicate]

In this answer, the function is defined as

With(Math)f=(a,b,c,d)=>...    (1)

However, f is not used in the function, so it seems fine to write

With(Math)(a,b,c,d)=>...

(the latter one's return value is also the function)

The point is that, you can't write

f = With(Math)(a,b,c,d)=>...

You either write (1) or

f = eval('With(Math)(a,b,c,d)=>...')

to make f be the function. Is that allowed?